Thermostatic pump



19, 1938. N. L. MERcuR- THERMOSTATIC PUMP Originai Filed -June 21, 1935 2 Sheets-Sheet 1 :77 I. v mvu'ron 45 s 42- MfAJA Patented Apr. 19, 1938' PATENT OFFICE- 2,114,567 Tnaan os'rA'rIc PUMP Nathan L. Mercur, McKeesport, Pa.

Application June 21, 1935, Serial No. 27,696 Renewed September 21, 1937 15 Claims.

it? moved thereby, so that the'efiiciency or powertransmitting ability of the thermostatic element as a pump will vary according to the amount of work which the pump may be called upon to do.

In illustrating my invention I have shown three bi-rnetal elements of different construction to function as impellers, and also arranged to modiiy their respective shapes to vary their pumping efficiency according to the temperature of the medium with'which they are to work.

20 In all three modifications of the thermostatic impellers embodying my invention, a provision is made for a certain amount of free leakage of bypassing of the controlled medium at all temperstores, in order that the impellers may be afiected 25 by the average or mean temperature of the medium to be controlled. 1

I have illustrated the three modifications, briefly referred to, in the accompanying drawings, in whichim Figure 1 is a plan view of a stamping of thermostatic metal as stamped from a fiat plate before it is formed to constitute an impeller;

Figure 2 is a plan view of the impeller disc after it is formed from the stamping of Figure 1;

Figure 3 is a vertical sectional view of the impeller taken along the lines 33 of the view shown in Figure 2;

Figure 4 is a side view, partially in elevation and partially in section, of the impeller disc of Figure 5 is an enlarged perspective view, partially in elevationv and partially in section,'of a radial rib or corrugation formed in the disc shown in Figure 2;

Figure 6 is a side view, partially in section and partially in elevation, of a pump assembly employing a bi-metal disc impeller of the form illustrated in Figure 2;

Figure 7 is a plan view or a strip of bi-metal from which a spiral impeller is to be formed for the second modification referred to above;

I Fisure 8 is a similar view of the strip of Figure 7, showing the manner in which one end of 5 the strip is curved by suitably crimping or cor- Figure 3, 'shown mounted. upon a rotatable drive rugating the strip by transverse corrugations along the length of the strip;

Figure 9 is a perspective front view of one of the corrugations formed in the strip in Figure 8, and illustrates the manner in which the corrugation 5 is tapered or inclined to establish a sharper, smaller curvature on one edge of the strip than on the other Figure 10 is a plan view of a spiral involute formed from the strip in Figure 8; 10

Figure 11 is a sectional view through a pump assembly provided with a bi-metal spiral formed as shown in Figure 10, with the spiral extended to constitute an involute screw;

Figure 12 is a plan view of the disc subdivided into vanes or segments with oi-metal strips secured to the edges of each vane on opposite sides thereof;

Figure 13 is a vertical edge view of the disc shown in Figure 12;

Figure 14 is, a side view of the discof Figure 12 illustrating the positions assumed by three vanes of the disc in response to'the flexing of the bi-metal strips when the temperature of the bimetal strips is changed from normal;

Figure 15 is a lower edge view of the disc of Figure 12;

Figure 16 is a front elevational view of one vane of the disc of Figure 12;

Figure 17 is a vertical section of the disc in its twisted position taken along the line i'|--l1 in Figure 16;

Figure 18 is a similar vertical sectional view of the vane in-Figure 16 taken along the line l8-I8 in Figure 16;

Figure 19 illustrates an assembly of the disc of Figure 12 on a motor shaft and within a housing to function as a motor operated blower; and

Figure 20 illustrates schematically an application of the motor driven blower of Figure 19 to a bread oven in which the temperature is to be maintained uniformly.

' As illustrated in Figure 1, a bi-metal element 2| is stamped from a sheet of bi-metal, substantially in the form illustrated, with corners of quartercircle shape and flat connecting side portions 23 between the adjacent quarter circle corner portioris. The stamped plate 2! is provided with a central opening 24, the edges of which are shaped or contoured in accordance with the correspond ing outer edges, to embody four quarter circle portions 25 concentric with the four outer portions 22, and four connecting straight edges 26 parallel to the outer edges of the portions between the corners. 55

I tially in a circle.

The bi-metal plate 2| of Figure 1 is then formed to constitute an impeller disc 30, as shown in Figure 2, in which the outer periphery is substan- The portions 23 between the quarter-circle corners 22 are bent laterally upward from the normal plane of the disc to con-- stitute four ribs or corrugations 21 extending radially inward from the periphery of the disc. In order to impart a slight cupping to the disc, the corrugations or ribs 2'! are inclined or tapered to be of slightly greater height, and therefore utilize more metal, adjacent the outer end of the rib near the periphery of the disc, as is illustrated in Fig ure 3. tain the shape of the disc substantially until a predetermined temperature is attained by the disc, at which time the accumulated stress will be sufiicient to overcome the cupping of the disc and cause the disc to snap over to a reversely cupped position with respect to the normal position that is shown in Figure 3.

In Figure 4, the disc 30 is illustrated in its normal condition mounted upon a rotatable drive shaft 32 and secured in position on the drive shaft by means of a suitable lock washer 33 and nut 34. In the normal cold position of the disc, as illustrated in Figure 4, the surrounding wall 35 within which the pump disc is normally disposed should be directly opposite the peripheral edges of the formed disc 30 and the ribs 21.

In Figure-5, a rib is illustrated to show the manner in which the ribs are gradually tapered from the relatively low portion of the rib adjacent the center of the disc to the higher portion of the rib adjacent the periphery of the rib.

In Figure 6 I have illustrated a pump structure 40, consisting of an intake housing 4|, an outlet housing 42, and a drive shaft 43 having a driving, pulley 44 on its outer end and a bimetalimpeller disc 30 mounted on the inner end. The shaft 43 extends through a bearing 45 on the intake housing 4|. A suitable packing medium 46 and a retaining gland 41 are schematically illustrated.

The intake housing 4| is provided with an intake port 48, and the outlet housing 42 is provided with outlet port 49. The inlet housing 4| is shown provided with a partition wall 5| on the inner edge of the inlet housing 4| between an inlet chamber 52 in the inlet housing 4| and an outlet chamber 53 in the out-let housing 42. The pump impeller and shaft are mounted so that the periphery of the impeller disc 30 will be adjacent to the surface of the partition wall 5|, and the relative dimensions of the orifice in the wall 5| are such that a small space 54 is left between the wall and the disc to permit a small amount of leakage of the cooling water past the disc.

So long as the temperature of the cooling water is below a predetermined value, the thermostatic disc impeller 30 will remain in the position illustrated in full line in Figure 6, where the periphery of the disc and the outer edges of the ribs 2'! will be opposite and adjacent the inner surface of the wall 5|. When the disc is rotated while in such position, the disc merely rotates within the water in the pump housing, without building up pressure to force the Water into the outlet chamber.

When the temperature of the water and of the disc increases to a predet'ermined'value, at which the action of the pump is desired for the purpose of increasing the flow of the cooling water, the disc flexes and snaps over to the cupped position in the opposite direction as illustrated by The purpose of such cupping is to mainthe broken lines 60 in Figure 6. The disc when rotating in such position receives the water from the intake chamber 52 by means of the radial ribs 21, and centrifuges the water into the outlet chamber, thus building up a pressure in the outlet chamber which serves to move the water under pressure through the outlet port 49 and through the circulating system to which the pump is connected.

So long as the temperature of the water circulated by the pump continues above the predetermined value for which the operation of the pump disc is adjusted, the disc will remain in its oppositely cupped position where it will circulate the cooling fluid under pressure. When the temperature of the cooling fluid diminishes to or below the temperature for which the pump disc is adjusted, the disc will snap back to its normal operating position at which only a relatively small amount of free circulation of the cooling fluid is permitted.

By means of the construction which is illustrated in Figure 6, the thermostatic disc which serves as the pumping element, adjusts or changes its position according to the temperature of the cooling fluid and does only so much work as is necessary to establish the best temperature in the cooling fluid for proper working conditions of the engine. 1

In Figures '7 to 10, inclusive, I have illustrated in simple fashion, the evolution or development of the thermostatic spiral member 6| which is employed as a. water propelling screw in the pump shown in Figure 11. The spiral member 6| which serves as the water propelling member is made from a narrow strip of bi-metal 62, as

illustrated in Figure '7, which is corrugated or crimped as shown in Figure 8 to embody spaced tapered corrugations 63 to introduce the proper and required amount of curvature in the strip to form the ultimate spiral 6| as illustrated in Figures 10 and 11.

As shown in Figure 9, the corrugations 53 are tapered, being higher at the inner edge 64 than 1 at the outer edge 65, in order to absorb the greater amount of metal that is available on the smaller are formed by the inner edge of the strip where it is curved. It will be obvious that the sizes and spacing of the corrugations will vary according to the amount of curvature required to make the strip assume the proper shape to form the spiral. By reason of the formation of the spiral in the manner illustrated, undesirable curving or concaving is prevented between opposite edges of any part of the strip. If the spiral were cut from a fiat plate, each convolution so formed would curve or form a concavity from edge to edge which would prevent proper movement of the spiral to form a screw as illustrated in Figure 11. By providing the same amount of metal on both edges of each convolution, however, by the method of forming that is illustrated, any tendency of each convolution to bend or buckle transversely of the convolution is obviated.

When the temperature of the water is below iii! proper desired temperature, the bi-metal spiral is substantially flat and closed, and only a nominal quantity of water passes through the cooling system to which the conduit 10 is connected. Under such conditions the spider and the bi-metal spiral merely rotate in the cooling medium. As the temperature of the cooling medium increases, however, to or beyond a desired maximum value, the spiral gradually opens up axially to form a screw for propelling the cooling medium through the conduit and the cooling system connected to the conduit.

The spiral thus gradually adapts its shape according to the temperature of the medium which is being propelled thereby, and, thus, according to the amount of work it is called 'upon to do.

In the remaining figures of the drawings, I have illustrated a fan-type propelling device in which a disc 15 is separated into several blades or vanes I6 that are individually controlled by two co-operating bi-metal elements 11 and 18 to bend the blades or vanes to compel them to assume a shape according to the temperature of the medium being propelled thereby as measured by the bi-metal strips l1 and '18. The disc 15 may be made of any suitable medium having sufficient resiliency or pliability to permit its form or shape to be changed or modified by the action of the thermostatic strips ll and 18. It may be made of thin metal or of a fabric. In either case, of course, it is desirable that the disc be in substantial dynamic balance.

As illustrated in the several detailed figures, the bi-metal strips l1 and it are mounted on opposite sides of each vane on the opposite edges thereof, in such manner as to be oppositely eilective in shaping the vane upon which they are to be mounted. For example, as illustrated in Figure i l, the middle vane i6 is acted upon by the two bimetal elements El and iii to move the opposite edges of the vane in opposite directions. Each of the other two vanes that are shown are illustrated as being correspondingly afiected by their respectively associated bi-metal strips. Figures 16, 17 and i8 serve further to illustrate the manner in which the bi-metal strips function to change the shape of a vane. In one predetermined normal temperature, the disc may assume a substantially flat shape, with all of the vanes in one plane or substantially so, as illustrated in Figure 13. When the temperature rises above such predetermined value, the vanes will be moved to one position as shown in Figure 14:, and, when the disc is rotated in one direction, the vanes will serve to propel the air or other medium away from. the blades in one direction. When the temperature diminishes below such predetermined normal, the vanes will be caused to assume an opposite pitch with respect to the normal position, and, when the disc is rotated in the same direction, the vanes will now move the medium in the opposite direction.

In Figure 19 the disc is illustrated as mounted upon a shaft 88 of a motor 8! to function as a blower, being supported to revolve in an encircling ring 82 that serves as the limiting conduit through which the disc may propel the air or other medium that is to be controlled.

In Figure 20 is illustrated one application in which such a blower or pump may be applied, to utilize the temperature-responsive character of the blades. Such responsiveness adjusts the blades so that they will function according to the requirements of the system in which they are employed.

ably propelled by two wheels 81 and 88 to carry a series of dough supporting trays 89 through a heated zone 90. The heat is supplied to the oven through a series of burners 9i schematically illustrated at the base of the oven. The space in the oven is suitably divided into two compartments by a horizontal partition 82 in order that the heated air inside the oven may be circulated in a closed path which corresponds to the locus of travel of the dough supporting trays 89.

The heated air in the oven is circulated by means of a motor driven fan 84 provided with thermostatically self-adjustable blades 85 of the character described. The blower 84 may be arof the air within the oven, 50 that the proper average temperature may be maintained throughout the path of travel of the trays that carry the dough.

I have thus illustrated in the accompanying drawings and in the foregoing description, three modifications or structures embodying the principle of my invention, according to which the blades or vanes of the impeller thermostatically respond to the temperature of the transferred medium so that the medium may be controlled to the extent that may be necessary to maintain a predetermined temperature.

My invention is therefore not limited to the specific details that are illustrated, since they obviously may be modified in structure and design without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim as my invention:

l. A thermostatic pump comprising a rotatable drive shaft and a bi-metal disc supported thereon to function as an impeller and formed to change its position in response to the temperature of the medium moved thereby, the bi-metal disc being formed to be relatively concave in one direc tion below a certain temperature, and to change position to be concave in the opposite direction above said temperature, the concavesuri'ace of the disc at the lower temperature being provided with radial ribs that serve as pumping impellers in both positions of the disc.

2. A thermostatic pump comprising a drive shaft and a bi-metal member supported thereon to function as an impeller, and formed to cen trifuge a medium to be moved thereby, to move the medium at a rate depending upon the ternperature of the medium, the bi-metal member, being a disc, being formed to be relatively concave in one direction below a certain temperature, and to change position to be concave in the opposite direction above said temperature, the concave surface of the disc at the lower temperature being provided with radial ribs that serve as pumping impellers in both positions of the disc.

3. A thermostatic pump comprising a housing having an inlet port and an outlet port, with a chamber adjacent each port and a wall with an orifice between the two chambers, a rotatable drive shaft supported to extend to or through the orifice between the two chambers, and a bimetal disc on the shaft to be rotated thereby, the disc normally filling the space within the orifice at one temperature, and formed to as- 1 sume such a different position at a predetermined diiferent temperatura'that the disc when rotated will then receive the medium from the inlet chamber and centrifuge it into the outlet chamber.

4. A thermostatic pump comprising a motor, and an impeller driven thereby, the'impeller being a cupped bi-metai disc capable of changing its shape or form from concave in one direction to concave in the opposite direction according to the temperature of the medium propelled thereby, and a group of radial bars on the disc to serve as impellers.

5. A thermostatic pump comprising a rotatable drive shaft and a thermally responsive impeller mounted on the shaft, and operable automatically to change its inclination to the axis according to the temperature of a medium propelled by the pu p- 6. A thermostatic pump comprising a housing having an intake port and an outlet port, an intake chamber and an outlet chamber, and a selfadjusting thermally-responsive disc impeller so disposed and of such shape as to rotate freely in the medium transferred by the pump, while the medium is below a predetermined temperature, and adapted to change position and shape, when the medium exceeds such temperature, in order to propel the medium into the outlet chamber and thence to the outlet port, the disc embodying radial vanes which are positioned to propel the medium into the outlet chamber only when the disc changes shape in response to the predetermined temperature.

"I. A thermostatic pump comprising a rotatable drive shaft, 2. thermostatic disc mounted thereon to rotate therewith, a housing enclosing the disc and providing an inlet chamber on one side of the disc and an outlet chamber on the other side of the disc, the disc embodying radial vanes and functioning to rotate freely in one position in the medium below a predetermined temperature and changing position above said temperature to 'ro tate the radial vanes to force the medium into the outlet chamber.

8. A thermostatic pump comprising a rotatable drive shaft and a bi-metal disc mounted thereon and provided with radial corrugations extending laterally from the face of the disc, the disc being shaped to be normally concave in one direction under a predetermined temperature and operative to reverse its direction of concavity above said temperature, and a housing around the shaft and disc provided with an inlet port and an outlet port and so positioned that the disc will centrifuge'the medium to be transferred towards the outlet port only when the disc reverses its concavity in response to a temperature above the predetermined operating temperature.

9. A thermostatic pump comprising a rotatable drive shaft and a bi-metal disc mounted thereon and cupped or concave in one direction below a predetermined temperature and adapted to reverse the direction of the concavity above said temperature, the disc embodying radial corruga-' tions or vanes by means of which the pumping action is effected when the disc changes its shape in response to a temperature exceeding the predetermined temperature.

10. A fluid pump consisting of a rotatable shaft supporting a disc of iii-metal provided with radial corrugations and having a concavity to be disposed to face a source or supply chamber of fluid, the disc being capable of reversing its concavity upon attaining a predetermined temperature, thereby to shift the position of the radial corrugations to communicate with a receiving chamber, whereby the fluid entering the concave corrugations may be forcibly centrifuged into the receiving chamber.

11. A thermal pump, for controlling the passage of fluid through a conduit, comprising a rotatable drive shaft and a disc concentrically mounted thereon transversely of the conduit, the disc being formed of bi-metal and normally cuppedin one direction below a predetermined temperature, and adapted to change shape in response to variations in the temperature of the fluid, thereby to vary the propelling effect of the disc upon the fluid.

12. A thermostatic pump comprising a rotatable drive shaft and a bi-metal member mounted on the shaft, a housing enclosing the bi-metal member and the shaft, the housing having an intake compartment and an outlet compartment, with the bi-metalmember serving as a substantial but incomplete barrier between the two compartments, while the temperature of the medium to be transferred by the pump is less than a pre-determined value, and the bi-metal member further operating to change its shape in response to the temperature of the medium to diminish its effect as a barrier and to become an actuator,

,as the temperature of the medium increases beyond such pre-determined value.

13. A thermostatic pump comprising a rotatable drive shaft and a bi-metal member mounted on the shaft and disposed in a passage to be traversed by a medium to. be propelled by the pump, the bi-metal member functioning as a substantial but incomplete barrier while the temperature of the medium is on one side of a pre-determined value, and the bi-metal member changing its shape to function as an actuator when the temperature of the medium moves beyond such pre-determined value.

14. A thermostatic pump comprising a rotatable drive shaft and a bi-metal member mounted on the shaft and operable automatically to change its relation to the shaftto function as a barrier or as an actuator for a medium in a passage in which the pump is disposed, the'bi-metal member serving, whenit changes its automatic relation to the shaft, to vary its function from barrier to propeller in response to the temperature of the medium being propelled by the pump.

15. A thermostatic pump. comprising a rotatable drive shaft and a bi-metal member mounted on the shaft and operable automatically to change-its relation to the shaft, and a housing forenclosing the shaft and the bi-metal member, withthe bi-metal member disposed in a passa'ge' formed in the housing, the bi-metal member functioning both as a valve and as an actuator, and responding to the temperature of the medi um traversing the pump in such manner as to varythe actuator or valve function according to the temperature of the controlled medium.

NATHAN L. MERCUR. 

